Methods for production of continuous stretches of circular cylindrical members, tools, use of a tool, a length of pipe and pipe parts

ABSTRACT

The present invention regards methods of projecting, producing and bending continuous stretches of circular cylindrical bodies, such as stretches of piping, handrails and rails for stair lifts. The invention also regards a tool for use with the method, application of a tool, and a length of pipe and fittings prepared for use with the method. During the project planning, the orientation of the fitting ( 52 ) is given in relation to the first piece of pipe ( 50 ), by the cut angle of the fitting ( 52 ) and the rotational angle (δ) of the fitting about the longitudinal axis of the pipe ( 50 ) relative to a defined spatial direction gen by a mark ( 53, 54 ) on the piece of pipe ( 50 ) and the fitting ( 52 ). During construction, the piece of pipe ( 50 ) is arranged with one side in a defined spatial direction, the fitting ( 52 ), which has a given cut angle, is fitted to the piece of pipe ( 50 ) and the fitting ( 52 ) is rotated through a pre-determined rotational angle (δ) that is measured relative to the defined spatial direction. A tool ( 70 ) with an angle gauge ( 74 ) is used to measure the rotational angle (δ). This angle gauge may be electronic. When bending lengths of pipe, a bending tool ( 60 ) is used, which tool is equipped with an angle gauge ( 66 ) for measuring the rotational angle of the length of pipe ( 61 ) about the longitudinal axis. A system for determining construction method and construction is also described.

The present invention regards methods of projection, production andbending of continuous stretches of circular cylindrical bodies, e.g.stretches of piping, hand rails and rails for stair lifts. The inventionalso regards a tool for implementing the method and an application of atool, a stretch of piping and fittings prepared for use with the method,along with a system for determining the construction method andconstruction parameters.

Each year, a countless number of kilometres of piping is laid on boardships, on offshore installations, in factories and other buildings.Considerable proportions of these stretches of piping extend acrossseveral levels and collectively present a very complicated shape. Inparticular on board ships, where conditions are often crowded and makingthe best possible use of the available space is of great importance,piping is laid at varying angles that often differ from straight angles.This is done in order to be able to lay the pipes as close to thebulkheads and ship's side as possible. As a result, laying pipes onboard ship is a very complicated task. Mistakes are often made, causingsmaller or larger amounts of piping to be scrapped.

In order to facilitate this work, a method has been in use over the last20 years that involves the use of isometric drawings in order to showthe stretch of piping with all its straight pieces of pipe and all thebends. This method has spread and gained recognition. Using this method,the centreline of the pipe is drawn, and the spatial positioning ofstraight pieces of pipe is indicated by means of the co-ordinates in thexyz direction of one end of the pipe in relation to the other end of thepipe. A bend is indicated by means of its cut angle, i.e. the angleacross which the bend extends.

In FIG. 1, the principle of such isometric drawings is shown. Thecentreline of the stretch of piping is drawn at 1. The stretch of pipingcan here be seen to come in along the y axis at the left hand side ofthe figure and be bent through a bend 2, through an angle that goes upand to the left relative to the y axis, at an angle κ, which is the cutangle. The cut angle for a bend will always be given. A bend can beproduced with a very accurate cut angle, or pipes may be bent to anequally accurate angle of bending. From the bend 2, the stretch ofpiping extends through a length L, before being deflected again at abend 3. The position of the bend 3 is given in relation to the positionof the bend 2, using co-ordinates x, y and z.

In FIG. 3, it has been illustrated how a stretch of piping may be shownby an isometric drawing.

Although such an indication of positioning for the stretch of piping isunique, in practice it is still not that simple to lay pipes accordingto a drawing of this type. Returning to FIG. 1 and imagining that thestretch of piping has been laid up to the bend 2, and that the pipe withlength L is about to be laid, it would be logical to mark the pointusing co-ordinates x, y and z, and then aim the pipe with length L atthis point. In practice however, the point xyx will be located in thinair, and it will be difficult, if not impossible to mark. The pipelayerwill therefore have to aim the pipe at what he can only assume to be thelocation of the point xyz. This will leave room for mistakes. Since thepipe that follows after the next bend, bend 3, is to be oriented on thebasis of co-ordinates which have their origin at the bend 3, aninaccuracy in the placement of the bend 3 will be carried over to theorientation of the pipe that follows the bend 3. In this manner,inaccuracies will constantly add up, and may in many cases lead to thestretch of piping ending up with a completely different positioning fromthat which was intended. Especially on board ships, on offshoreinstallations and in factories, a offset position for the stretch ofpiping may have serious consequences. In this case, poor utilisation ofthe space is the least of the worries. Among the more seriousconsequences is that of being left with insufficient space for theequipment that is to be positioned after the piping has been laid, thatof not allowing other stretches of piping to be laid according to plan,that of necessitating dismantling and reconstruction of large parts ofthe piping, and that of causing great delays during construction, whichstaggers other construction processes.

In order to remedy any inaccuracies that are discovered duringconstruction, the pipelayer will often adjust the stretch of piping byadding extra bends and/or cutting pieces of pipe. This often entailswelding of pipes or insertion of extra unions, which may later causeproblems with leakage, which is particularly serious if the extra joinends up in a place that later becomes very inaccessible. Using today'stechnology, it is practically impossible to bend pipes accurately inmore than one plane, i.e. all bends must be in the same plane.

From prior art is known a tool, described in CA 970962, which is used todetermine the centreline through a pipe. The tool consists of agraduated element shaped as a quarter circle and an angular elementattached to the graduated element. The angular element is equipped witha level.

A pipe bending machine is known from US 4625531. By using this machine,it is possible to bend subsequent bends that have been rotated through180° relative to each other. However bending of bends that have beenrotated through an arbitrary number of degrees is not described.

In order to avoid the above problems and other problems associated withthe known methods of producing stretches of piping, a method has beenprovided for production of a stretch of piping, which method is based onan isometric drawing and makes use of other parameters than the xyzco-ordinates in determining the orientation of pieces of pipe.

In a first aspect, the invention regards a method of projecting astretch of piping or similar, in which the stretch of piping comprisesat least one piece of pipe and a fitting, and which is characterised inthat the orientation of the fitting is given relative to the first pieceof pipe in terms of the cut angle of the fitting and the rotationalangle of the fitting about the longitudinal axis of the pipe, relativeto a defined spatial direction.

In a second aspect, the invention regards a method for production of astretch of piping or similar, in which the stretch of piping comprisesat least one fitting and a second piece of pipe, and which ischaracterised in that the piece of pipe is arranged with one side in adefined spatial direction; the fitting, which has a given cut angle, isfitted to the piece of pipe and the fitting is rotated through apredetermined rotational angle, by the rotational angle being measuredrelative to the defined spatial direction.

In a third aspect of the present invention, it regards a method ofproducing at least parts of stretches of piping or similar throughbending, in which a bend is bent on a length of pipe, and which ischaracterised in that the bend is bent to a given angle of bending andwith a predetermined rotational angle that is measured relative to adefined side of the length of pipe, and which is to face in a definedspatial direction upon assembly of the length of pipe.

The invention also regards a length of pipe for production of at leastparts of a stretch of piping or similar, and is characterised in that itcomprises a mark along one side parallel to the longitudinal axis, whichmark is to face in a defined spatial direction upon assembly of thelength of pipe.

The invention further regards a fitting for joining with pieces of pipeand/or fittings, for production of a stretch of piping or similar, whichfitting comprises two or more legs, and is characterised in that thefitting comprises a mark at least at or near the end of each of itslegs, which mark is to face in a defined spatial direction upon assemblyof the fitting.

The invention also regards application of a tool for use in productionof a stretch of piping or similar, comprising a means of measuring anangle along the circumference of a piece of pipe or a fitting with acircular cross section and a means of determining a reference plane, formeasuring the rotational angle of another piece of pipe or anotherfitting to be connected.

Furthermore, the invention regards a tool comprising a means ofmeasuring an angle along the circumference of a piece of pipe or afitting with a circular cross section and a means of determining areference plane, and is characterised in that the means of measuring anangle and the means of determining the reference plane comprise anelectronic circuit with an electronic level and angle gauge.

The invention also regards a tool for bending lengths of pipe, and ischaracterised in that it is provided with an angle gauge for measuringthe rotational angle of the length of pipe about the longitudinal axis.

Finally, the invention also regards a system for determining the choiceof construction method and construction parameters when producing astretch of piping, characterised by a first storage device forproduction restricting parameters, which contains production restrictingparameters such as bend radius and structural dimensions of flanges foravailable parts, maximum bend radius, minimum gripping length andmaximum length of pipe between bends for a bending machine, a secondstorage device for input of site specific parameters such as availablelength in the X direction, available length in the Y direction,available length in the Z direction, direction of incoming connectionand direction of outgoing connection, a third storage device for inputof optional parameters such as the desired deviation for the stretch ofpiping, an evaluation unit for, on the basis of said parameters,establishing whether or not the conditions for bending the stretch ofpiping and/or producing this from assembled parts are right, acalculation unit that, on the basis of the stored parameters, determinesthe construction parameters for the stretch of piping, such asbending/cut angles and rotational angles for bends, as well as lengthsof straight lengths of pipe, and a display or print unit for display ofsaid bending/cut angles, rotational angles and lengths, preferably inthe form of a graphic representation of the stretch of piping.

Further embodiments of the invention are given in the dependent claims.

The present invention provides many advantages. Among these are:

-   -   The work becomes easier, and the demands placed on the person        doing the work are less stringent. Specialists with lower        qualification requirements may be used.    -   Less time consuming. In many cases, one operative may be used        instead of two, for the same task.    -   A considerable increase in accuracy.    -   The consumption of materials is reduced, due among other things        to fewer mistakes.    -   Allows a greater degree of prefabrication.    -   An increase in productivity and job satisfaction.

The principles of the present invention may be implemented withoutcostly changes or expensive new equipment. The method is also easy tolearn. The existing isometric drawings may still be used, with onlyminor changes.

The invention will now be explained in greater detail with reference tothe accompanying figures, in which:

FIG. 1 illustrates a known method for production of a stretch of piping,

FIG. 2 illustrates the principles of the present invention,

FIG. 3 shows a projected stretch of piping according to the knownmethod,

FIG. 4 shows a projected stretch of piping according to the method ofthe present invention,

FIG. 5 shows the “points of the compass” for the diagrams in FIGS. 3 and4,

FIGS. 6 and 7 show two bends with different cut angles and how thecentreline is defined through these,

FIG. 8 shows a tool for measuring rotational angle,

FIG. 9 shows a piece of pipe and a bend assembled at a given rotationalangle,

FIGS. 10–13 show bending of pipes in a bending machine,

FIG. 14 shows a tool according to the present invention,

FIG. 15 shows an alternative way of representing a stretch of pipinggraphically in accordance with the present invention,

FIG. 15 a shows a symbol for specification of rotational angle, and

FIG. 16 illustrates a system for determining the choice of constructionmethod and construction parameters.

In FIG. 1, the principles of the known isometric method of producing astretch of piping are shown. The centreline of the stretch of piping isdrawn as a thick line at 1. In the figure, the stretch of pipingconsists of a first piece of pipe 1 a, a second piece of pipe 1 b and athird piece of pipe 1 c. The pieces of pipe 1 a and 1 b are joined via abend 2, and the pieces of pipe 1 b and 1 c are joined via a bend 3. Thebend 2 has a predetermined cut angle κ. The bend is normally producedwith this cut angle in advance, and as such the cut angle is extremelyaccurate. The piece of pipe 1 b has a length L, and is also cut inadvance. From the figure, it can be seen that the piece of pipe 1 b isto be joined with the piece of pipe 1 c at a point located at theco-ordinates x1, y1, z1 in a system of co-ordinates with its origin inthe bend 2. The co-ordinates x1, y1, z1 form the sides of an imaginaryparallelepipedic box B with right angles, where the piece of pipe 1 bforms the diagonal between two of the opposite corners of the box, wherethe bend 2 is in one corner and the bend 3 is in the opposite corner.With this orientation of the piece of pipe 1 b, the cut angle κ may beresolved into an angle β that lies in the horizontal plane, and an angleα that lies in the vertical plane. The angles α and β are not given inthe drawing but may be calculated by use of a well-known arrangement offormulae. Pipelayers have developed various techniques for aligningpieces of pipe in the xyz direction. Placing marks on walls and floorsand aiming for these, and the use of conventional spirit levels in orderto determine the most common angles, for instance 45°, are among these.However all these techniques entail a high degree of uncertainty, anderrors are carried over from one bend to the next, adding up so that theresulting error may end up being quite large.

FIG. 3 shows a stretch of piping represented by the dimensions that areused with the known method. For instance, it may be seen that the lengthof 150 mm is given for the piece of pipe 4. The piece of pipe forms acut angle of 45°, in a bend 6, with the adjoining piece of pipe 5, andthe piece of pipe 4 is to extend to a bend 7 that is 125 mm horizontallyand 83 mm vertically from the bend 6. The vertical distance of 83 mmconstitutes the height of the imaginary box, and the measurements of thebase of the box are 106 mm and 66 mm.

FIG. 2 shows the principle of the method according to the presentinvention. This also has an imaginary box B drawn around the piece ofpipe 1 b. This is done to make the comparison with the known method ofFIG. 1 easier, however the measurements of the sidewalls of the box areactually completely without interest when using the new method accordingto the present invention. The cut angle ic is however still of interest.In FIG. 3 is also drawn another angle, the angle δ. The angle δ is theangle between the vertical edge 10 of the box B, at the end face 11opposite the bend 2, and on the opposite side in relation to the bend 3,and the diagonal 12 of the end face between the bend 3 and the corner 13opposite the bend 3 on the end face I. Put differently, the angle δ isthe rotational angle between the piece of pipe 1 a and the piece of pipe1 b.

FIG. 4 shows the same stretch of piping as in FIG. 3 but here presentedby means of the principles of the present method. Looking at the pieceof pipe 4 again, it can be seen that the cut angle of the adjoining bend6 is also here given as 45°. In addition, the 38,5° rotational angle ofthe bend 6 is given. The 106 mm edge and the 106 mm diagonal of the endface of the imaginary box is also given in the figure, in order toillustrate the rotational angle. However it is not necessary to givethese measurements in order to produce the stretch of piping. Althoughit is most practical to produce the stretch of piping in an isometricdrawing, it is obviously also possible to produce it in other ways, e.g.in a plan drawing or as a table.

Even though the principles of the invention in the above and in thefollowing have been described in connection with advanced forms ofpipework construction, these principles may also, possibly in a modifiedversion, be used in traditional plumbing in order to ensure and keepcontrol of the correct angles in pipe bends and similar.

In FIGS. 6 and 7, two bends have been shown in order to illustrate howthe centreline is defined through a bend. The bend 20 in FIG. 6 has acut angle of 90°. A first centreline 21 extends normally to the crosssection at the first opening 22 of the bend 20, and goes through thebend 20 until it meets a second centreline 23, which extends normally tothe cross section at the other opening 24 of the bend 20. In this casethe crossing point 25 between the two centrelines will fall outside ofthe bend 20. The distance 26 between the crossing point 25 and theopenings 22 and 24 respectively is the overall length of the bend.

FIG. 7 shows a bend 30 with a cut angle of 45°. Here, the crossing point35 falls between centrelines 31 and 33 inside of the bend 30. Theoverall length 36 of the bend 30 is shorter than the overall length 26of the bend 20.

FIG. 8 shows a tool 40 that can be used to produce a stretch of pipingin accordance with the method of the present invention. The toolconsists of a plate 41. A curved cutout 42 is formed in the plate 41,which cutout has approximately the same radius of curvature as a pipe43, on which the tool is to be used. A graduated degree scale 44 isprovided along the cutout 42, with 0° halfway along the cutout 42. Alevel is placed in one of the edges 45 of the plate 41, parallel to theline tangential to the cutout at 0°. The level is a liquid-filled tubewith a small air bubble. The level 46 is used to determine thehorizontal plane.

By letting a mark 47 along the pipe 43 be flush with 0° when the level46 is in the horizontal plane, the mark 47 may be oriented upright. Anyangle along the circumference of the pipe 43 may be measured on thebasis of this mark 47. In the figure, a mark 48 is has been left at 30°.

In FIG. 9 there is shown a part of a piece of pipe 50 and a piece ofpipe 51. A bend 52 is arranged between these in such a manner that thebend 52 joins the pieces of pipe 50 and 51. A mark 53 is made on thepiece of pipe 50. This mark is a line extending along the entire pieceof pipe 50, parallel with its longitudinal axis. A similar mark 54 ismade on the bend 52. The mark 53 is shaped so as to be oriented in a setdirection, preferably upwards. The mark 54 is arranged along theshortest side of the bend 52. I.e. if the mark 54 is also turnedupwards, the leg of the bend 52 to which the piece of pipe 51 is joinedwill also face upwards. In order to effect the rotational angle δbetween the piece of pipe 50 and the piece of pipe 51, the mark 54 isrotated through the number of degrees that corresponds to the angle δfrom the mark 53. The exact rotational angle is measured e.g. by use ofthe tool 40 in FIG. 8.

FIGS. 10–12 show a bending machine 60 for bending a length of pipe 61.The bending machine 60 comprises a bending head 62 equipped with agroove 63 and with a curvature corresponding to the curvature of thepipe 61. The bending machine 60 also comprises a retaining jaw 64. Whenthe length of pipe 61 is to be placed in the machine, the retaining jaw64 and the bending head 62 are first pulled apart, so that the pipe maybe inserted between these. Then the retaining jaw 64 and the bendinghead 62 are brought together around the pipe 61. In order to bend thepipe 61, the bending head 62 is rotated through a certain angle aboutits rotational axis as shown in FIG. 12. This angle of bendingcorresponds to the cut angle on separate bends.

In FIG. 10, the length of pipe 61 has been mounted in the bendingmachine 60. A bend 65 has already been bent in a previous bendingprocess. The new bend is to have a specific rotational angle relative tothe existing bend 65, which rotational angle is given in the projectdrawings, e.g. as shown by bend 6 in FIG. 4. The length of pipe may bepre-equipped with a longitudinal mark defining 0° rotation. In order togive the new bend the correct rotational angle, it is merely necessaryto rotate the length of pipe through the correct number of degrees aboutthe longitudinal axis. For this purpose, the bending machine may, asshown in FIG. 13, be provided with a graduated degree scale 66, forinstance on the retaining jaw 64 and/or the bending head 63. By thismethod, it is no longer necessary to think of the direction, in whichthe previous bend extends, as the correct rotational angle will alwaysbe given as a set number of degrees from the 0° mark. An arbitrarynumber of bends in any direction may thus be bent with great accuracyonto a continuous length of pipe. The requirement for jointing of pipeswill therefore be greatly reduced.

By the above method, it is no longer necessary to think of where in theroom a bend should be located. The spatial position of the bend is givenby the rotational angle δ and the length L of the piece of pipe. Thedimensions of the box B are therefore no longer of interest, and agraphical representation of the stretch of piping may be produced bystating only the cut angle κ the rotational angle δ and the length L ofthe piece of pipe.

By the method according to the present invention there will always be areference line oriented in a set direction. This direction is preferablyupwards, and the pipes and bends are pre-equipped with a mark thatshould face upwards during assembly. When a bend is to be joined to thispiece of pipe with one leg, the bend is rotated about the longitudinalaxis of the piece of pipe, through the number of degrees given by therotational angle of the bend. The pipelayer will then know that theother leg of the bend is pointed in the desired direction, and the nextpiece of pipe will end up exactly in the intended position.

Any errors that occur will no longer propagate to the next bend, as therotational angle of the bend is always measured from one set spatialdirection and not oriented relative to the end point of the previouspiece of pipe.

In FIG. 14, there is shown a tool 70 according to the present invention.The tool comprises a plate 71 in which is formed a cutout 72. A mark 73has been made halfway along the cutout, which mark defines zero. Thetool also comprises an electronic level with a display 74. Theelectronic level may be set to zero in an arbitrary angular position byuse of a push button 75, and may thereby define 0° in any angularposition. By using another push button 76, the level may be reset sothat the angle shown in the display is relative to the horizontal plane.The electronics in such electronic levels are well known to a personskilled in the art, and will therefore not be described in greaterdetail herein.

When the electronic tool is used, it is rotated from the zero mark onthe pipe until the correct rotational angle shows in the display. Atthis point, the mark 73 will be at the correct rotational angle, and abend may be fitted at this angle. The possibility of setting the displayto zero also makes it possible to measure relative angles, i.e.differences in angles. This may in some cases be appropriate. It mayalso be appropriate to store the angles in an internal memory.

The tool 70 is also equipped with a laser 77 that emits a laser beam 78,for example with the same angle relative to the horizontal plane as thatshown by the electronic level. Instead of a tool provided with a cutoutthat is matched to one pipe diameter, it is also possible to produce atool that can be used with several pipe diameters. In an embodiment (notshown) this tool may for instance have two legs set at right angles toeach other. The tool is placed against the pipe in such a manner thateach leg abuts the pipe at one point. The tool zero is where the legsmeet. By an electronic tool, it will be possible to determine therotational angle by rotating the tool from the initial position untilthe correct rotational angle shows in the display, and mark the point onthe pipe directly opposite the tool zero.

In order to mark pipes that are not pre-equipped with a longitudinalmark for definition of 0°, the tool 70 is equipped with a scriber 79.The tool is also equipped with rollers 80 along one edge. The distancebetween the outer edge of the rollers 80 and the scriber 79 correspondsto the radius of a pipe with the same curvature as that of the cutout72. By placing the pipe on a support and passing the tool 70 along thepipe with the rollers 80 against the support and the scriber against thepipe, a mark may be made along a pipe.

As an electronic level is relatively expensive, it may be appropriatefor this to be moveable from the plate 71 to other plates with a cutoutof a different radius of curvature, matched to pipes of a differentdiameter. It is also appropriate for the level to be moveable to aconventional straight level, a reel or other. If so desired, the entireplate 71 with the level may be fitted to another tool.

FIG. 15 shows an alternative way of presenting a stretch of pipinggraphically, which may be used instead of the depiction in FIG. 4. Theadvantage of the manner of presentation in FIG. 15 is that it requiresless space, is simpler to read and gives direct information that is easyto communicate. It makes it easier to utilise information withoutconversions, and it is not necessary to consider the shape of thestretch of piping.

Instead of drawing a bend as an angle, it is in FIG. 15 given only bystating the angle of bending/cut angle for the bend in number ofdegrees. The rotational angle is also given as number of degrees anddirection of rotation from the reference direction (up). In FIG. 15 a, asymbol is shown that illustrates the principle of specifying therotational angle for bends. + signifies that the bend rotates in theclockwise direction seen in the direction from the starting point of thestretch of piping towards the destination point.− signifies rotation ofthe bend in the anti-clockwise direction. Degrees are counted from theupward direction.

The arrow 90 indicates the starting point and the direction ofadvancement for constructing the stretch of piping. A symbolcorresponding to FIG. 5 will normally also be added to the drawing inorder to define the direction relative to the ship or the building inwhich the stretch of piping is to be installed. In the example shown inFIG. 15, the first element of the stretch of piping is a straight lengthof 35 mm pipe 91. Then follows a 90° bend 92 that points straight up(rotation 0°), the next element is a straight length of 330 mm pipe 93,followed by a 35° bend 94 that has been rotated through 90° in theanti-clockwise direction (i.e. pointing to the left seen in thedirection of construction). After this follows a straight length of 1060mm pipe, followed by a 90° bend 96 that has been rotated through 180°(i.e. points straight down), which again is followed by a straightlength of 492 mm pipe 97. Then follows a 90° bend 98 that has beenrotated through 0° (i.e. points straight up), followed by a straightlength of 500 mm pipe 99.

FIG. 16 depicts a flow chart showing a system for calculation of cutangles/angles of bending, rotational angles and lengths of pipes forstretches of piping. The system may for instance be implemented througha computer programme in a portable PC or a pocket computer.

Parameters have been input in advance, which parameters limit what maybe constructed through bending or joining of pipe fittings (representedby the box 100). This may be a selection of bending radii for pipebends, overall dimensions for end flanges, maximum bending radius forthe available bending machine, the minimum gripping length of thebending machine, the maximum straight length of pipe that can be handledby the bending machine and other similar parameters. These parameterswill as a rule have the same values from one time to the next but may bealtered if the selection of pipe fittings changes or a new bendingmachine is obtained.

At 101 the user inputs parameters that are specific to the constructionsite. In a simple case, this is the available length in the x, y and zdirections. A three-dimensional body 103 has been shown in order toillustrate this. It may however also be imagined that dimensions and thepositioning of elements located within the three-dimensional body 103,such as strengthening rings or equipment, may be input. At 104, the userinputs additional site specific parameters; the direction of incomingpipes, defined in the x, y and z direction, and the direction ofoutgoing pipes in the x, y and z direction. Incoming pipes may forinstance be a pump nozzle, and outgoing pipes may for instance be apressure vessel nozzle. At 105 is illustrated an incoming pipe in thenear lower corner 106, and an outgoing pipe in the far upper corner 107.

At 108, the operator states the preferred course for the stretch ofpiping. This may be expressed by giving the type of deviation. Maximumdeviation is present when the length of the longest straight stretch ofpiping is as long as possible, i.e. when the angles of bending/cutangles of the bends are as small as possible. This case is illustratedby 109, by a bent stretch of piping 110. Here, there is a small lengthof pipe 111 before a bend 112. This because the bending machine has acertain gripping length represented by the length of pipe 111. Thelongest length of pipe is denoted 113, and is followed by a bend 114 anda small length of pipe 115. Minimum deviation is present when the lengthof the longest straight stretch of piping is as short as possible, i.e.when the angles of bending/cut angles of the bends are approximatelystraight. This case is illustrated by 116. Here, a short straight lengthof pipe 117 is followed by a 90° bend 118 and a straight length of pipe119, which is again followed by a 90° bend 120 and a straight length ofpipe 121. Selection of the type of deviation depends on severalcircumstances. If it is desirable to leave as much room as possiblewithin the three-dimensional body 103, e.g. to be used for positioningof other equipment, as storage space or similar, it is sensible tochoose minimum deviation. If this is not essential, but it is desirableto limit the total length of piping and avoid sharp bends, it issensible to choose maximum deviation. An intermediate between maximumand minimum deviation can also be imagined. This may as an example beexpressed as a percentage of maximum deviation.

Instead of expressing the desired piping course as a specification ofdeviation, it is also possible to define this parameter in a differentmanner, for instance by indicating a plan for the longest length of pipeor a desired cut angle/angle of bending for the first bend.

At 122 is shown an example of maximum deviation when the incoming pipelies in the y direction and the outgoing pipe lies in the z direction.

When these parameters have been put into the system, the possibleconstruction methods are checked out. As a rule, it is desirable toproduce a stretch of piping by means of bending, as this requires lesswork, gives greater security against leaks and saves materials. Thesystem therefore performs a calculation (illustrated by 123) in order tofind out whether the stretch of piping can be bent. If this is notpossible, a calculation is performed to find out whether is can beassembled from available parts. The result of this is communicated tothe user via a display (illustrated by 124 and 125). The algorithms forperforming these calculations are known per se, but are very long-windedwhen carried out manually.

The user then chooses (illustrated by 126) between bending andconstruction by means of parts. It is also possible to request aprintout of the drawing of the piping course (illustrated by 127) fromthe system. In this case, the system not only calculates cutangles/angles of bending and lengths of pipes; it also calculates therotational angle for each pipe bend. These parameters are added to thedrawing, such that the pipelayer may easily bend or assemble a stretchof piping on the basis of the drawing (illustrated by 128). Instead ofprinting out the drawing on paper, it may obviously also be shown on adisplay. The parameters may also be transferred to a drawing programmeand be used during construction.

Although the above essentially describes pipes and stretches of piping,the invention also comprises projection, production, bending and partsfor other long and narrow circular cylindrical or approximately circularcylindrical bodies that are to extend from one location to anotherthrough one or more bends, branches or other, and where it isappropriate to apply the present invention.

When the word fittings is used in the above, this is taken to includebends, branching elements, saddles, armature and other components to bejoined with the stretch of piping. As an example, it also includesflanges and nozzles integrated with pumps, filters and other componentsthat are connected to the stretch of piping.

The invention is only limited by the following claims and equivalents ofthese. The term pipe will in this context be understood in a verygeneral and wide sense, and comprises all bodies with a circularcylindrical or approximately circular cylindrical cross section and acertain longitudinal extent.

Although the principles of the present invention have in the aboveprimarily been described in the context of piplaying onboard ships, theinvention may naturally be used wherever pipes or pipe-like elements areto be joined in a specific configuration.

1. A method of projecting stretches of piping, in which the stretch ofpiping comprises at least a first piece of pipe and a second piece ofpipe and a fitting connecting the first and second pieces of pipe, andin which the second piece of pipe is to be oriented in a defineddirection from the fitting and the defined direction is to be given bygiving a set of parameters of which parameters a cut angle (κ) of thefitting is one, comprising the steps of: determining the defineddirection of the second piece of pipe relative to the fitting bydetermining the cut angle (κ) of the fitting, and determining arotational angle (δ) of the fitting about a longitudinal axis of thefirst piece of pipe in relation to a defined spatial direction, so thatthe rotational angle (δ) of the fitting becomes a parameter for thedefined direction of the second piece of pipe; and indicating therotational angle (δ) of the fitting in a graphic illustration of apiping course.
 2. The method according to claim 1, further comprisingthe step of deciding that the defined spatial direction is up inrelation to the first piece of pipe.
 3. A method of producing a stretchof piping, in which the stretch of piping comprises at least a fittingand a piece of pipe, comprising the steps of: positioning the piece ofpipe with one side oriented in a defined spatial direction; fitting thefitting, which has a given cut angle (κ), to the piece of pipe; rotatingthe fitting through a pre-determined rotational angle (δ) relative tothe defined spatial direction; measuring the rotational angle (δ) of thefitting in relation to the defined spatial direction; and therebyarranging the fitting in a pre-determined spatial direction defined bythe cut angle (κ) and the rotational angle (δ).
 4. The method accordingto claim 3, further comprising the step of making a mark on that side ofthe piece of pipe which is to face in the defined spatial direction. 5.The method according to claim 3 or 4, further comprising the steps of:making a mark on the fitting, orienting the mark in the defined spatialdirection, and rotating the fitting about the longitudinal axis of thepiece of pipe until the mark on the fitting is at an angular distance(δ) from the mark on the piece of pipe that corresponds to the givenrotational angle (δ).
 6. The method of claim 3, wherein the piece ofpipe for production of at least parts of a stretch of piping comprises amark along one side parallel with the longitudinal axis of the stretchof piping, the method further comprising the steps of: assembling thepiece of pipe with the which mark is to face facing in a defined spatialdirection; using the mark as a reference mark for a fitting that isfitted to the piece of pipe; rotating the fitting through apre-determined rotational angle (δ) relative to the defined spatialdirection; and measuring the rotational angle (δ) of the fittingrelative to the defined spatial direction.
 7. The method of claim 3,wherein the fitting for joining with pieces of pipe or fittings forproduction of a stretch of piping, comprises two or more legs, and thefitting comprises a mark on each of the two or more legs, the methodfurther comprising the steps of: orienting the mark in a defined spatialdirection upon assembly of the fitting; using the mark as a referencemark for a second fitting or a piece of pipe; fitting the second fittingor the piece of pipe to the fitting; rotating the second fitting or thepiece of pipe through a pre-determined rotational angle (δ) relative tothe defined spatial direction; and measuring the rotational angle (δ) ofthe second fitting or the piece of pipe in relation to the definedspatial direction.
 8. The method of claim 6 or 7, wherein furthercomprising the step of drawing, imprinting or scribing the mark is as acontinuous line on the piece of pipe or the fitting.
 9. The method ofclaim 3, further comprising the steps of: providing a means of measuringan angle along the circumference of a piece of pipe or a fitting with acircular cross section; and providing a means of determining a referenceplane, wherein the means of measuring an angle and the means ofdetermining a reference plane comprise an electronic circuit with anelectronic level and angle gauge.
 10. The method of claim 3, furthercomprising the steps of: determining a reference plane by using a toolcomprising a means of determining a reference plane, measuring therotational angle (δ) relative to the reference plane, of a further pieceof pipe or a further fitting to be connected to a first piece of pipe orfirst fitting, by using a tool comprising a means of measuring an anglealong the circumference of a piece of pipe or a fitting with a circularcross section.
 11. The method of claim 10, where the means of measuringan angle and the means of determining the reference plane comprise anelectronic circuit with an electronic level and an electronic anglegauge.
 12. The method of claim 3, the method further comprising thesteps of: employing a system for determining the choice of constructionmethod and construction parameters when producing stretches of piping;storing production limiting parameters in a first storage device of saidsystem; storing site specific parameters in a second storage device ofsaid system; storing optional parameters in a third storage device ofsaid system; establishing in an evaluation unit, on the basis of saidparameters, whether or not the conditions are right for bending thestretch of piping or producing the stretch of piping from assembledparts; determining in a calculation unit, on the basis of saidparameters, the construction parameters for the stretch of piping; anddisplaying or printing bending/cut angles, and rotational angles andlengths.
 13. The method of claim 12, wherein said further comprising thestep of displaying or printing a graphic presentation including astraight line for each straight piece of pipe and a marking for eachbend, said marking including the values for the bending or cut angle (κ)for said respective bend and the rotational angle (δ) for saidrespective bend.